Dawsonia superba is a moss in the family Polytrichaceae that is found in Australia, New Guinea, Malaysia,[2] and New Zealand.

[4] It has analogous structures to those in vascular plants that support large size, including hydroid and leptoid cells to conduct water and photosynthate,[4] and lamellae that provide gas chambers for more efficient photosynthesis.

[5] D. superba is a member of the class Polytrichopsida, although it has a sporophyte that is unique from other hair-cap mosses.

The gametophyte is the haploid stage of the life cycle, and is composed of leaves, a stem, and root-like rhizoids.

[5] Lamellae have been referred to as "pseudo-mesophyll", meaning that they are analogous to mesophyll structures in vascular plant leaves, which also aid in gas exchange.

The wax acts as a hydrophobic barrier, so that air spaces in the lamellae are protected from both drying out and over-saturation from rainwater.

These teeth are arranged circularly in multiple rows and form a brush-like turf through which spores are released.

[17] The gametophytes of D. superba are dioicious, meaning that the male and female reproductive structures are housed on separate plants.

The male reproductive structure, or antheridium, produces sperm that must reach a female archegonial plant in order for fertilization to occur.

[18] Leaves, when isolated from the rest of the plant, have been shown by Selkirk (1980) to develop protonemal filaments, although this regeneration is rare in D. superba compared to other members of the genus.

Therefore, high photosynthetic efficiency and some sort of water transport system is necessary for plants to reach a certain height.